Assessment of Microwave Pretreatment and Enzymolysis Optimization of the Lotus (Nelumbo Nucifera, Gaertn) Seed Protein

Abstract

In order to study the impact of heat on the Degree of Hydrolysis (DH) of the Lotus Seed Protein (LSP), a heat-pretreatment before enzymolysis under high-power microwave irradiation was carried out. Additionally, parameters of enzymatic hydrolysis including substrate concentration, pH, temperature, papain concentration, and enzymolysis time were optimized using Response Surface Methodology (RSM). The results showed that under high-power microwave irradiation sub bonds of the protein break, causing disaggregation and unfolding of the secondary structure, precisely a decrease in the intermolecular aggregate structure and increase in the random coil structure, making the protein bonds susceptible to papain during the enzymolysis. As for the analysis of the optimization results by RSM, it revealed that the optimal enzymolysis conditions were at a protein substrate concentration of 15 g/L, pH of 5.5, enzymolysis temperature of 57°C, papain amount of 0.5 g/L, and enzymolysis time of 45 min, for which the predicted value of the DH was 35.64%. The results of this study showed that microwaves also have significant potential applications in the field of food enzymolysis.